Fresno, Calif., was rated worst, with an overall score of 21.5. San Francisco topped the list with a score of 74.

The Trust for Public Land studied the 40 largest cities in the country as part of its new “ParkScore” rating system released this month. The land-conservation organization used mapping technology with demographic data to determine how well cities fared when it came to providing park space for citizens.

Scoring was based on three factors:

•Park access: What percentage of the city's residents live within a 10-minute walk to a park?

•Park size: What percentage of a city’s land area is committed to park use?

•Services and investment: How much money is spent on parks per capita? How many playgrounds are available per 100,000 city residents?